Process of Synaptic Transmission(Cholinergic Synapse)

Question 1

what is the first step of synaptic transmission across a cholinergic synapse?

Answer 1

• an action potential arrives at the synaptic knob of the pre synaptic neurone
• the action potential generates the voltage gated calcium ion channels to open in the presynaptic neurone
• Ca2+ then diffuse into the synaptic knob

Question 2

what is the second step of synaptic transmission across a cholinergic synapse?

Answer 2

• influx of calcium ions into the synaptic knob causes synaptic vesicles to fuse with the presynaptic membrane
• vesicles release acetylcholine into the synaptic cleft by exocytosis

Question 3

what is the third step of synaptic transmission across a cholinergic synapse?

Answer 3

• acetylcholine diffuses across the synaptic cleft and binds to receptors on the postsynaptic membrane
• this causes the sodium ion channels in the postsynaptic neurone to open
• influx of sodium ions into the post synaptic membrane cause depolarisation
• action potential on postsynaptic membrane is generated if threshold level is reached
• acetylcholine is removed so response doesn’t keep occuring and this is done by an enzyme called acetylcholinesterase, and the products are absorbed back into the presynaptic neurone to make more acetylcholine